I have a '70 SS 396 with the D-99 Two-Tone paint option the top is 10 (white-painted) & the lower color is 25(astro blue). Does anyone know how many of these were made in '70? I have been told it is a rare option.

Two-tones were considered passe by most people back then; the 'in' crowd went for vinyl roof covers. I have never seen a '70 SS with 2-tone (heard of a '69 and a '67) and I can only recall 1 two-tone '70 Chevelle way back. It was a Canadian 300-deluxe coupe in Forest Green with Frost Green roof (and wheels!)
BTW I'm not sure that D99 necessarily refers to the 2-tone; it may just be referring to the moldings. I have seen a few that were coded with D99 but carried solid paint codes on the firewall. Vinyl top and 2-tone cars got the roof moldings, but they were also offered for solid paint cars.

I have one.It is a 70 ss 396,came from Florida originaly when sold new and ended up here in Ohio.I painted it back to its factory color #58 Autumn Gold Matalic with #10 Classic White stripes,but at the time i did not paint the roof White.The paint is about 6 years old and shows a little wear needs a new one maybe this time it will get its white roof ? My build sheet confirms it all and my cowl tag shows the #58 and #10.Get back with me i would like to talk to you more about this you are the first one i have seen to have one.Here is a picture http://ohiochevelle.com/images/Henderson/cocobh.htm